The only thing holding me back from the x-s1 now (aside from saving the cash) is the knowledge that there are still faulty units out there. Is there a way to tell if the unit is faulty without opening the box? By that I mean can you tell when the camera was manufactured by looking at the box?

Some people say the serial number is on the box but if 23..that is no gaurantee anyway. If you buy from a shop you are not obliged to buy the camera even if you ask to inspect a new camera in the box.